Apparatus and method for accessing and performing a function within an intervertebral disc

ABSTRACT

Apparatus and methods are disclosed for accessing the interior of an intervertebral disc to perform a function within the disc. One such apparatus comprises a catheter having a lumen; and a guide wire having a distal portion and a proximal portion, and configured to be positioned within and moved relative to the lumen of the catheter; wherein the guide wire is capable of navigating itself within an intradiscal section of the intervertebral disc to a selected section of the disc and the catheter is capable of being advanced relative to the guide wire such that the catheter follows a path of the guide wire within the intradiscal section of the disc to the selected section. These apparatus and methods may be used for the treatment of intervertebral disc disorders such as sealing fissures of the annulus fibrosus, which may or may not be accompanied with contained or escaped extrusions. These apparatus and methods may also be used, for example, for the removal or addition of material to the intervertebral disc.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the priority of U.S. Provisional Application No.60/185,221 filed on Feb. 25, 2000, entitled “Apparatus And Method ForAccessing And Performing A Function Within An Intervertebral Disc.” Theabove application is hereby incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to methods and apparatuses for modifyingintervertebral disc tissue and more particularly to the treatment ofannular fissures and disc defects using percutaneous techniques to avoidmajor surgical intervention.

2. Description of Related Art

Intervertebral disc abnormalities have a high incidence in thepopulation and may result in pain and discomfort if they impinge on orirritate nerves. Disc abnormalities may be the result of trauma,repetitive use, metabolic disorders and the aging process and includesuch disorders but are not limited to degenerative discs (I) localizedtears or fissures in the annulus fibrosus, (ii) localized discherniations with contained or escaped extrusions, and (iii) chronic,circumferential bulging discs.

Disc fissures occur rather easily after structural degeneration offibrous components of the annulus fibrosus during a part of the normalaging process that may be accelerated by trauma. Sneezing, bending orjust attrition can tear these degenerated annulus fibrosus fibers,creating a fissure. The fissure may or may not be accompanied byextrusion of nucleus pulposus material into or beyond the annulusfibrosus. The fissure itself may be the sole morphological change, aboveand beyond generalized degenerative changes in the connective tissue ofthe disc. Even if there is no visible extrusion, biochemicals within thedisc may leak out of the contained intervertebral disk and irritatesurrounding structures. Disc fissures can also be debilitatinglypainful. Initial treatment is symptomatic, including bed rest, painkillers and muscle relaxants. More recently, spinal fusion with cageshave been performed when conservative treatment did not relieve thepain. The fissure may also be associated with a herniation of thatportion of the annulus.

With a contained disc herniation, there are no free nucleus fragments inthe spinal canal. Nevertheless, even a contained disc herniation isproblematic because the outward protrusion can press on the spinalnerves or irritate other structures such as the corresponding nerveroot. In addition to nerve root compression, escaped nucleus pulposuscontents may chemically irritate neural structures. Current treatmentmethods include reduction of pressure on the annulus by removing some ofthe interior nucleus pulposus material by percutaneous nuclectomy.However, complications include disc space infection, nerve root injury,hematoma formation, instability of the adjacent vertebrae and collapseof the disc from a decrease in height.

Another disc problem occurs when the disc bulges outwardcircumferentially in all directions and not just in one location.Overtime, the disc weakens and takes on a “roll” shape orcircumferential bulge. Mechanical stiffness of the joint is reduced andthe joint and spinal column may become unstable. One vertebrae maysettle on top of another. This problem continues as the body ages andaccounts for a shortened stature in old age. With the increasing lifeexpectancy of the population, such degenerative disc disease andimpairment of nerve function are becoming major public health problems.As the disc “roll” extends beyond the normal circumference, the discheight may be compromised, foramina with nerve roots becomes compressed.In addition, osteophytes may form on the outer surface of the disc rolland further encroach on the spinal canal and foramina through whichnerves pass. This condition is called lumbar spondylosis.

It has been thought that such disc degeneration creates segmentalinstability which disturbs sensitive structures which in turn registerpain. Traditional, conservative methods of treatment include bed rest,pain medication, physical therapy or steroidal injections. Upon failureof conservative therapy, spinal pain (assumed to be due to instability)has been treated by spinal fusion, with or without instrumentation,which causes the vertebrae above and below the disc to grow solidlytogether and form a single, solid piece of bone. The procedure iscarried out with or without discectomy. Other treatments includediscectomy alone or disc decompression with or without fusion.Nuclectomy can be performed by removing some of the nucleus to reducepressure on the annulus. However, complications include disc spaceinfection, nerve root injury, hematoma formation, and instability ofadjacent vertebrae.

These interventions have been problematic in that alleviation of backpain is unpredictable even if surgery appears successful. In attempts toovercome these difficulties, new fixation devices have been introducedinto the market, including but not limited to pedicle screws andinterbody fusion cages. Although pedicle screws provide a high fusionsuccess rate, there is still no direct correlation between fusionsuccess and patient improvement in function and pain. Studies on fusionhave demonstrated success rates of between 50% and 67% for painimprovement, and a significant number of patients have more painpostoperatively. Therefore, different methods of helping patients withdegenerative disc problems need to be explored.

FIGS. 1A and 1B illustrate a cross-sectional anatomical view of avertebra and associated disc and a lateral view of a portion of a lumbarand thoracic spine, respectively.

Structures of a typical cervical vertebra (superior aspect) are shown inFIG. 1A: 104—lamina; 106—spinal cord; 108—dorsal root of the spinalnerve; 114—ventral root of the spinal nerve; 116—posterior longitudinalligament; 118—intervertebral disc; 120—nucleus pulposus; 122—annulusfibrosus; 123—anterior longitudinal ligament; 126—vertebral body;128—pedicle; 130—vertebral artery; 132—vertebral veins; 134—superiorarticular facet; 136—posterior lateral portion of the annulus;138—posterior medial portion of the annulus; and 149—spinous process. InFIG. 1A, one side of the intervertebral disc 118 is not shown so thatthe anterior vertebral body 126 can be seen. FIG. 1B is a lateral aspectof the lower portion of a typical spinal column showing the entirelumbar region and part of the thoracic region and displaying thefollowing structures: 118—intervertebral disc; 126—vertebral body;142—spinous process; 170—inferior vertebral notch; 110—spinal nerve;174—superior articular process; 176—lumbar curvature; and 180—sacrum.

The presence of the spinal cord and the posterior portion of thevertebral body, including the spinous process, and superior and inferiorarticular processes, prohibit introduction of a needle or trocar from adirectly posterior position. This is important because the posteriordisc wall is the site of symptomatic annulus tears and discprotrusions/extrusions that compress or irritate spinal nerves for mostdegenerative disc syndromes. The inferior articular process along withthe pedicle and the lumbar spinal nerve, form a small “triangular”window through which introduction can be achieved from a posteriorlateral approach. FIG. 1D is an overhead view of an instrumentintroduced by the posterior lateral approach. It is well known to thoseskilled in the art that percutaneous access to the disc is achieved byplacing an introducer into the disc from this posterior lateralapproach, but the triangular window does not allow much room tomaneuver. Once the introducer pierces the tough annulus fibrosus, theintroducer is fixed at two points along its length and has very littlefreedom of movement. Thus, this approach has allowed access only tosmall central and anterior portion of the nucleus pulposus. Currentmethods do not permit percutaneous access to the posterior half of thenucleus or to the posterior wall of the disc. Major and potentiallydangerous surgery is required to access these areas.

Accordingly, these problems with spinal column surgery have beenaddressed by Applicants in U.S. Pat. Nos. 5,980,504, 6,007,570, U.S.application Ser. No. 09/363,824, filed Jul. 30, 1999, U.S. applicationSer. No. 09/236,816 filed Jan. 25, 1999, U.S. application Ser. No.09/162,704 filed Sep. 29, 1998, U.S. application Ser. No. 09/153,552filed Sep. 15, 1998 and U.S. application Ser. Nos. 08/881,525,08/881,692, 08/881,694, all filed Jun. 24, 1997, which are incorporatedby reference

Accordingly, it is desirable to provide an improved access apparatus andmethod by which the interior nucleus of an intervertebral disc may beaccessed and annular fissures or herniations can be treated or repaired.It would be further desirable to provide a modular exchange system toaddress various functions such as delivery of energy, delivery ofmedicaments, removal of material or providing access for physical andchemical modification of the nucleus and annulus.

SUMMARY OF THE INVENTION

The present invention provides novel apparatus and methods for accessingintervertebral disc, as well as diagnosing and treating intervertebraldisc disorders. In one embodiment, an apparatus is provided foraccessing a selected section of an intervertebral disc. The apparatuscomprises a catheter having a lumen; and a guide wire having a distalportion and a proximal portion, and configured to be positioned withinand moved relative to the lumen of the catheter; wherein the guide wireis capable of navigating itself within an intradiscal section of theintervertebral disc adjacent an inner wall of an annulus of the disc tothe selected section of the disc and the catheter is capable of beingadvanced relative to the guide wire such that the catheter follows apath of the guide wire within the intradiscal section of the discadjacent the inner wall of the annulus of the disc to the selectedsection.

According to this embodiment, the guide wire is built to possess (a)sufficient rigidity to be advanceable through a nucleus pulposus andaround the inner wall of an annulus fibrosus under a force appliedlongitudinally to the proximal end of the core wire, (b) insufficientpenetration ability to be advanceable out through the annulus fibrosusunder the applied force, and (c) sufficient flexibility in a directionof a disc plane to be compliant with the inner wall.

Also according to this embodiment, the distal portion of the guide wireincludes a spring coil to adjust flexibility of the guide wire. Aforming ribbon may be incorporated in the distal portion of the guidewire to support the spring coil. The spring coil may be fully coatedwith Teflon or other biocompatible materials. The distal portion of theguide wire may be tapered to a smaller diameter toward the distal end.

Still according to this embodiment, the distal portion of the guide wirehas a distal tip at the extremity of the distal portion of the guidewire. The distal portion of the guide wire may have one or more flatsides. The distal tip may be configured to be non-piercing through anannulus fibrosus, for example, including a blunt tip or a rolling balltip. The distal tip may also include a locking mechanism for securingthe guide wire within the selected section of the intervertebral disc,such as within an intradiscal section of the disc adjacent an inner wallof an annulus of the disc. The locking mechanism may include aretractable hook or a plurality of directional hooks. Alternatively, theguide wire may be capable of cross-locking itself once the guide wire isadvanced to the selected section of the disc.

Still according to this embodiment, the proximal portion of the guidewire may preferably have an outer diameter between about 0.005-0.025inches. The distal portion of the guide wire may preferably have anouter diameter between about 0.002-0.012 inches. The proximal portion ofthe guide wire may preferably be between about 10-15 inches long. Thedistal portion of the guide wire may preferably be between about 0.2-1.2inches long. The distal portion of the guide wire may preferably have alength at least one-half of a diameter of the nucleus pulposus.

The apparatus of the present invention may further include a dialatorsheath configured to be slid or passed over the guide wire forintroducing the catheter onto the guide wire.

The guide wire of the apparatus may be actively steerable. At least aportion of guide wire may be radiographically visible.

The guide wire of the apparatus may have a bending stiffness as measuredin Taber stiffness units preferably between about 2-400 and morepreferably about 3-150 units in a desired bending plane. The distalportion of the guide wire may have a column strength preferably betweenabout 0.2-7 kg, and more preferably between about 0.7-4 kg.

The catheter of the apparatus may further include a functional elementfor performing a function adjacent the selected section, such asdelivering energy, adding material and removing material. In one aspect,the functional element may also be an irrigation lumen extending from aproximal end of the catheter to the intradiscal section. In anotheraspect, the functional element may comprise a thermal energy deliverydevice. A thermal energy source may be operably attached to the thermalenergy delivery device through the catheter. Examples of the thermalenergy delivery devices include, but are not limited to, microwaveprobes, optical fibers, radio frequency electrodes, thermal resistiveheaters, integrated circuits and ultrasound emitters.

The functional element may be capable of delivering a controlled amountof energy at or near the fissure such that no vaporization occurs at ornear the fissure when energy is delivered by the functional element.Optionally, the functional element may be capable of delivering acontrolled amount of energy at or near the fissure such that no materialother than water is removed at or near the fissure when energy isdelivered by the functional element. Also optionally, the functionalelement may be capable of delivering a controlled amount of energy at ornear the fissure such that no destructive lesion is formed on a disc ator near the fissure when energy is delivered by the functional element.

The catheter of the apparatus may further comprise at least one sensorcapable of monitoring temperature, power, voltage or a combinationthereof and the input from the sensor controls energy supplied to thethermal energy device.

In another embodiment of the present invention, a method of treating anintervertebral disc is provided. The method comprises: causing a guidewire to navigate itself within an intradiscal section of theintervertebral disc adjacent an inner wall of an annulus of the disc toa selected section of the disc; taking a catheter which has the guidewire positioned within a lumen of the catheter; and advancing thecatheter relative to the guide wire such that the catheter follows apath of the guide wire within the intradiscal section of the discadjacent the inner wall of the annulus of the disc to the selectedsection.

According to this embodiment, causing the guide wire to navigate itselfmay include applying a longitudinal force to the guide wire which issufficient to advance the guide wire through the nucleus pulposus andaround the inner wall of an annulus fibrosus, but which force isinsufficient for the guide wire to puncture the annulus fibrosus.

Also according to this embodiment, the selected section of the disc maybe a posterior medial, posterior lateral, anterior lateral, or anteriormedial section of the annulus fibrosus, or a combination thereof.

Still according to this embodiment, the method may further includeperforming a function adjacent the selected section by using a catheterthat includes a functional element for performing the function. Thefunction may be delivering energy, adding material and removingmaterial. For example, the functional element may be a heating elementcoupled with a temperature sensor. Such a heating element may be a coilheating element, a flat heating element, or a flex ribbon heatingelement. Alternatively, the guide wire itself may include a heatingelement.

The method according to the present invention may further include usingthe function to treat annular fissures, for example, by addingsufficient energy to the selected section of the disc. The sufficientenergy may be added to shrink the collagen component of the annulusfibrosus around the fissure or to cauterize granulation tissue in thefissure.

Alternatively, the functional element may be a lumen capable ofdelivering or aspirating material. Accordingly, the method may furtherinclude placing a material in the disc. Such a material may beelectrolyte solutions, contrast media, pharmaceutical agents,chemonucleolytic enzymes, hydrogel, osteoinductive substances,chondrocyte-inductive substances, sealants, collagen, fibrinogen andthrombin, and any combination thereof.

Accordingly, an advantage of the invention is to provide a simple andmaneuverable apparatus for accessing the interior of an intervertebraldisc. The apparatus should be able to advance and navigate through thenucleus pulposus and along the annulus fibrosus to provide access to thesite of the annular fissure.

Still a further advantage of the invention is to provide a device whichhas a distal end that is inserted into the disc and access theposterior, posterior lateral and posterior medial regions of the innerwall of the annulus fibrosus.

Another advantage of the invention is to provide an apparatus and methodwhich is exchangeable over the access portion of the invention toprovide various functions within the intervertebral disc such asdiagnostic viewing, energy delivery, mechanical manipulation, removal oraddition of material, delivery of medicament and pain management. Theconstruction of the separate guide wire and catheter is advantageous inthat both structural units may be designed separately without relying ona single structure for both support and treatment.

The accompanying drawings, which are incorporated in and form a part ofthis specification, illustrate embodiments of the invention and,together with the description, serve to explain the principles of theinvention.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1A is a superior cross-sectional anatomical view of a cervical discand associated vertebral structure.

FIG. 1B is a lateral anatomical view of a portion of a lumbar spine.

FIG. 1C is a posterior-lateral anatomical view of two adjacent lumbarvertebrae.

FIG. 1D is a superior cross-sectional view of a specified posteriorlateral approach into a herniated intervertebral disc.

FIG. 2 is a cross-sectional view of an intervertebral disc with aportion of an intervertebral apparatus of the present invention insertedinto an intervertebral disc with a fissure along a posterior aspect ofthe annulus fibrosus.

FIG. 3 is a plan view of a guide wire of the invention showing a centralportion, a distal flexible section and a distal tip.

FIG. 4A is a cross-sectional view of the guide wire of the presentinvention including a specific embodiment of a tapered guide wire at thedistal flexible section.

FIG. 4B is a cross-sectional view of the guide wire of FIG. 4A with atreatment catheter positioned proximally over the guide wire.

FIG. 4C is a cross-sectional view of a specific embodiment of the guidewire of the present invention with a ribbon-shaped core section at thedistal flexible section.

FIG. 5A illustrates a partial cross-sectional view of the intervertebraldisc with an introducer inserted into the disc.

FIG. 5B is a partial cross-sectional view of the guide wire of thepresent invention inserted through the introducer of FIG. 5A andnavigated and positioned along a specified posterior aspect of theintervertebral disc.

FIG. 5C is a cross-sectional view of the core wire of FIG. 5B remainingin place at after the introducer is removed.

FIG. 5D is a cross-sectional view of the guide wire of FIG. 5B with adialator sheath inserted into the intervertebral disc over the guidewire.

FIG. 5E is a partial cross-sectional view of the guide wire and dialatorsheath of FIG. 5D with a treatment catheter inserted over the guide wireto the desired treatment site along the posterior aspect of theintervertebral disc.

FIG. 5F is a partial cross-sectional view of the guide wire andtreatment catheter of FIG. 5E after the sheath is removed.

FIG. 5G is a cross-sectional view of a specific embodiment of theapparatus of the present invention wherein the treatment catheterremains within the dialator sheath and the guide wire is removed.

FIG. 6A is a partial cross-sectional view of a specific embodiment ofthe apparatus of the invention illustrating a guide wire with a distallocking tip within a dialator sheath.

FIG. 6B is a partial cross-sectional view of the apparatus of FIG. 6Awith the dialator removed.

FIG. 7A is a partial cross-sectional view of a specific embodiment ofthe apparatus according to the present invention illustrating a guidewire with a preformed shape which crosses through the nucleus to lock onan anterior aspect of the intervertebral disc within the dialator.

FIG. 7B is a partial cross-sectional view of the apparatus of FIG. 7Aillustrating the removal of the dialator.

FIG. 8A is an illustration of the guide wire and introducer according tothe present invention with a section of the distal portion of thetreatment catheter being extended over the guide wire.

FIG. 8B is a detailed longitudinal cross-sectional view of the distalportion treatment catheter of FIG. 8A over the guide wire having aheating element and a temperature sensor.

FIG. 8C is a cross-sectional view of the distal portion of the treatmentcatheter of FIG. 8B showing the guide wire placement within thecatheter.

FIG. 9A is a cross-sectional view of a specific embodiment of the distaltip of the guide wire according to the present invention with a hooklocking tip.

FIG. 9B is a detailed cross-sectional view of the distal tip of theguide wire of FIG. 9A showing the hook locking tip retracted within thedistal tip.

FIG. 10 is a plan view of a specific embodiment of the guide wire of thepresent invention with a coil at the distal flexible portion and adirectional hook locking tip.

FIG. 11 is a simplified plan view of a guide wire using a pre-shapedform to retain a curved shape after deployment.

FIG. 12A is a plan view of the heating element of the treatment catheterof FIG. 8B with a helical coil structure.

FIG. 12B is a plan view of a specific embodiment of the heating elementof the catheter of FIG. 8B with a flat structure.

FIG. 12C is a plan view of a specific embodiment of the heating elementof the catheter of FIG. 8B with a ribbon structure.

FIG. 12D is a plan view of a specific embodiment of the heating elementof the catheter of FIG. 8B using a distal portion of the guide wire as amonofilament heating element.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

The present invention provides novel apparatus and methods for accessingand performing functions within an intervertebral disc, particularly fortreating intervertebral disc disorders such as sealing fissures of theannulus fibrosus, which may or may not be accompanied with contained orescaped extrusions. The present invention may also involve the removalor addition of material to the intervertebral disc.

In one embodiment, an apparatus is provided for accessing a selectedsection of an intervertebral disc. The apparatus comprises a catheterhaving a lumen; and a guide wire having a distal portion and a proximalportion, and configured to be positioned within and moved relative tothe lumen of the catheter; wherein the guide wire is capable ofnavigating itself within an intradiscal section of the intervertebraldisc adjacent and/or through an inner wall of an annulus of the disc tothe selected section of the disc and the catheter is capable of beingadvanced relative to the guide wire such that the catheter follows apath of the guide wire within the intradiscal section of the disc to theselected section.

According to this embodiment, the guide wire is built to possess (a)sufficient rigidity to be advanceable through a nucleus pulposus andthrough and/or around the inner wall of an annulus fibrosus under aforce applied longitudinally to the proximal end of the core wire, (b)insufficient penetration ability to be advanceable out through theannulus fibrosus under the applied force, and (c) sufficient flexibilityin a direction of a disc plane to be compliant with the inner wall.

Also according to this embodiment, the distal portion of the guide wireincludes a spring coil to adjust flexibility of the guide wire. Aforming ribbon may be incorporated in the distal portion of the guidewire to support the spring coil. The spring coil may be fully coatedwith Teflon or other biocompatible materials. The distal portion of theguide wire may be tapered to a smaller diameter toward the distal end.

Still according to this embodiment, the distal portion of the guide wirehas a distal tip at the extremity of the distal portion of the guidewire. The distal portion of the guide wire may have one or more flatsides. The distal tip may be configured to be non-piercing through anannulus fibrosus, for example, including a blunt tip or a rolling balltip. The distal tip may also include a locking mechanism for securingthe guide wire within the selected section of the intervertebral disc,such as within an intradiscal section of the disc adjacent an inner wallof an annulus of the disc. The locking mechanism may include aretractable hook or a plurality of directional hooks. Alternatively, theguide wire may be capable of cross-locking itself once the guide wire isadvanced to the selected section of the disc.

Still according to this embodiment, the proximal portion of the guidewire may preferably have an outer diameter between about 0.005-0.025inches. The distal portion of the guide wire may preferably have anouter diameter between about 0.002-0.012 inches. The proximal portion ofthe guide wire may preferably be between about 10-15 inch long. Thedistal portion of the guide wire may preferably be between about 0.2-1.2inch long. The distal portion of the guide wire may preferably have alength at least one-half of a diameter of the nucleus pulposus.

The apparatus of the present invention may further include a dialatorsheath configured to be slid or passed over the guide wire forintroducing the catheter onto the guide wire.

The guide wire of the apparatus may be actively steerable. At least aportion of guide wire may be radiographically visible.

The guide wire of the apparatus may have a bending stiffness as measuredin Taber stiffness units preferably between about 2-400 and morepreferably about 3-150 units in a desired bending plane. The distalportion of the guide wire may have a column strength preferably betweenabout 0.2-7 kg, and more preferably between about 0.7-4 kg.

The catheter of the apparatus may further include a functional elementfor performing a function adjacent the selected section, such asdelivering energy, adding material and removing material. In one aspect,the functional element may also be an irrigation lumen extending from aproximal end of the catheter to the intradiscal section. In anotheraspect, the functional element may comprise a thermal energy deliverydevice. A thermal energy source may be operably attached to the thermalenergy delivery device through the catheter. Examples of the thermalenergy delivery devices include, but are not limited to, microwaveprobes, optical fibers, radio frequency electrodes, plasma and/or iongenerators, and ultrasound emitters.

The functional element may be capable of delivering a controlled amountof energy at or near the fissure such that no vaporization occurs at ornear the fissure when energy is delivered by the functional element.Optionally, the functional element may be capable of delivering acontrolled amount of energy at or near the fissure such that no materialother than water is removed at or near the fissure when energy isdelivered by the functional element. Also optionally, the functionalelement may be capable of delivering a controlled amount of energy at ornear the fissure such that no destructive lesion is formed on a disc ator near the fissure when energy is delivered by the functional element.

The catheter of the apparatus may further comprise at least one sensorcapable of monitoring temperature, power, voltage or a combinationthereof and the input from the sensor controls energy supplied to thethermal energy device.

For example, an apparatus of the present invention is in the form of anexternally guidable guide wire and a catheter with a lumen for accessingand modifying the intradiscal structure and environment within or aselected location of an intervertebral disc having a nucleus pulposusand an annulus fibrosus, the annulus having an inner wall. Use ofvarious exchange-type catheters for different functions provides avariable and highly modifiable treatment system for delivering energy,adding or removing material from the intervertebral disc. For ease ofreference to various manipulations and distances described below, thenucleus pulposus can be considered as having a given diameter in a discplane between opposing sections of the inner wall. This nucleus pulposusdiameter measurement allows instrument sizes (and components ofinstruments) designed for one size disc to be readily converted to sizessuitable for an instrument designed for a different size of disc such asthe difference between cervical and lumbar discs.

The operational portions of the apparatus of the present invention areguided to a location in or near the annular fissure in the annulus ofthe intervertebral disc using techniques and apparatuses typical ofpercutaneous interventions. For convenience and to indicate that theapparatus of the invention can be used with any insertional apparatusthat provides access and proximity to the intervertebral disc, includingmany such insertional apparatuses known in the art, the term“introducer” is used to describe this aid to the apparatus and method.An introducer has an internal introducer lumen with a distal opening ata terminus of the introducer to allow insertion and subsequentmanipulation of the operational portions of the apparatus through thebody into and within the interior of a disc.

In another embodiment of the present invention, a method of treating anintervertebral disc is provided. The method comprises: causing a guidewire to navigate itself within an intradiscal section of theintervertebral disc adjacent an inner wall of an annulus of the disc toa selected section of the disc; taking a catheter which has the guidewire positioned within a lumen of the catheter; and advancing thecatheter relative to the guide wire such that the catheter follows apath of the guide wire within the intradiscal section of the discadjacent the inner wall of the annulus of the disc to the selectedsection.

According to this embodiment, causing the guide wire to navigate itselfmay include applying a longitudinal force to the guide wire which issufficient to advance the guide wire through the nucleus pulposus andthrough and/or around the inner wall of an annulus fibrosus, but whichforce is insufficient for the guide wire to puncture the annulusfibrosus.

Also according to this embodiment, the selected section of the disc maybe a posterior medial, posterior lateral, anterior lateral, or anteriormedial section of the annulus fibrosus, or a combination thereof.

Still according to this embodiment, the method may further includeperforming a function adjacent the selected section by using a catheterthat includes a functional element for performing the function. Thefunction may be delivering energy, adding material and removingmaterial. For example, the functional element may be a heating elementcoupled with a temperature sensor. Such a heating element may be a coilheating element, a flat heating element, or a flex ribbon heatingelement. Alternatively, the guide wire itself may include a heatingelement.

The method according to the present invention may further include usingthe function to treat an annular fissure, for example, by addingsufficient energy to the selected section of the disc. The sufficientenergy may be added to shrink the collagen component of the annulusfibrosus around the fissure or to cauterize granulation tissue in thefissure and thus, stimulate a healing response by the body.

Alternatively, the functional element may be a lumen capable ofdelivering aspirating material. Accordingly, the method may furtherinclude placing a material in the disc. Such a material may beelectrolyte solutions, contrast media, pharmaceutical agents,chemonucleolytic enzymes, hydrogel, osteoinductive substances,chondrocyte-inductive substances, sealants, collagen, fibrinogen andthrombin, and any combination thereof.

The method of the present invention which involves accessing the nucleuspulposus of an intervertebral disc is easily carried out with anapparatus according to the present invention.

In general, an introducer is provided that is located in a patient'sbody so that its proximal end is external to the body and the distalopening of its lumen is internal to the body and (1) internal to theannulus fibrosus or (2) adjacent to an annular opening leading to thenucleus pulposus, such as an annular tear or trocar puncture thatcommunicates with the nucleus pulposus.

A guide wire is slid into position within and through the introducerlumen so that a distal tip of the guide wire is positioned at theselected location of the disc by advancing or retracing the guide wirein the introducer lumen and optionally twisting the proximal end of theguide wire to precisely navigate the guide wire. By carefully selectingrigid characteristics of the guide wire and with a flexible distalportion and blunt non-traumatic distal tip and by careful selection ofthe flexibility in one plane versus the orthogonal plane, the distalportion of the guide wire will curve along the inner wall of the annulusfibrosus as it is navigated and is selectively guided to an annular tearor fissure at selected locations within the intervertebral disc.

A treatment catheter with a lumen for at least the guide wire ispositioned over the guide wire and slid over the guide wire andnavigated to the distalmost portion of the guide wire within the disc.The treatment catheter is configured to provide a function selected fromablation or shrinkage, delivery of medicaments, suction, viewing ormonitoring within the disc, ultrasound delivery for treatment,mechanical manipulation, and/or ionization of disc tissue.

The treatment catheter may also be “exchanged” such that varioustreatment modalities incorporated into separate catheters can bepositioned and slid over the guide wire to provide various treatmentswithout removal of the guide wire thereby providing less trauma to thepatient. In addition, such exchangeability and versatility of theapparatus maximizes the variety of functions to be performed within theintradiscal section of the disc without potentially costly constructionof various catheters each having a built-in guide wire.

The following descriptions of FIGS. 1 to 12 describe specificembodiments of the invention. The guide wire and treatment catheter ofthe present invention is illustrated but is not limited to thisembodiment. The descriptive language used both in the specification andclaims is for the purposes of clarity and convenience and not with anypurpose or implied limitation to the surgical art or along a columnarvertebral structure as is typical in the spinal column.

Reference will now be made in detail to the preferred embodiments of theinvention, examples of which are illustrated in the accompanyingdrawings. While the invention will be described in conjunction with thepreferred embodiments, it will be understood that they are not intendedto limit the invention to those embodiments. On the contrary, theinvention is intended to cover alternatives, modifications andequivalents, which may be included within the spirit and scope of theinvention as defined by the appended claims.

Referring now to FIG. 2, the anatomy of an intervertebral disc isillustrated with an apparatus according to the present inventioninserted into the disc. Structures of the disc are identified anddescribed by these anatomical designations: 136—posterior lateral innerannulus, 138—posterior medial inner annulus, 122—annulus fibrosus,120—nucleus pulposus, 146—annulus/dural interface, 148—annulus/posteriorlongitudinal ligament interface, 150—anterior lateral inner annulus, and152—anterior medial inner annulus. The method and treatment according tothe present invention are approached from the posterior aspect 103 ofthe intervertebral disc towards the anterior aspect 102 of the disc.

FIG. 2 illustrates that the mechanical characteristics of flexibledistal section 30 of guide wire 10 are selected to have (1) sufficientcolumn strength along the longitudinal axis of the guide wire to be ableto advance and push through the nucleus pulposus 120 and (2) differentflexural strengths along two axes orthogonal to the longitudinal axis toallow controlled bending of the guide wire 10. These parameters make theguide wire easily conformable and guidable along or directly throughinner wall 22 of the annulus fibrosus 122 to reach a desired location,such as the posterior wall along posterior medial annulus 138. Distaltip 20 of the guide wire 10 is preferably anti-traumatic such that theguide wire does not penetrate through the fissures or tears 44 in theannulus.

Guide wire 310 is illustrated in one embodiment in FIG. 3. The guidewire 310 consists of a core with a generally constant diameter from aproximal portion to a distal tip 320. A flexible distal portion 330 islocated at or near the distal tip 320 of guide wire 310. A coil 315 ispositioned at or near the distal tip such that a differentialflexibility characteristic allows the guide wire to navigate through thenucleus pulposus of the disc.

Referring to FIG. 4A, the guide wire 410 is configured with a taperingsection 411 which provides a differential bending stiffness through thedistal portion 425 of the guide wire. Flexible distal portion 430includes a coil 415 which allows the tapering section 415 to curve andto navigate along the wall of the annulus. Blunt distal tip 420 limitsand prevents the distal tip from penetrating large fissures in theannulus fibrosus.

In FIG. 4B, the catheter 400 is shown with a lumen 401 which is largeenough to pass over the guide wire 410. The catheter 400 is sized topass over the distal portion 425 and flexible distal portion 430 anddistal tip 420. It is preferable that the catheter 400 have a largerdiameter than the entire core guide wire 410 such that the distal end ofthe catheter may extend beyond the placement of the distal end 420 ofguide wire 410.

FIG. 4C is another specific embodiment of the guide wire 410 wherein thedistal tip portion 425 has flat core 412 at the distal end throughflexible distal portion 430. The flattened ribbon configuration of flatcore 412 allows the coils around distal tip 415 to have even greaterflexibility when navigating through the nucleus of the intervertebraldisc. The distal tip 420 is a blunt tip to provide an anti-penetrationcharacteristic. In will be appreciated that distal tip 420 may beconfigured as a ball which is soldered to the flat core 412 forprotection and steerability of the core wire 410.

Referring now to FIG. 5A, the intervertebral disc is illustrated with aposterior aspect 103 and an anterior aspect 102. The introducer 540 isinserted through the body into the nucleus pulposus 120 of the disc. Theintroducer needle has a hub 545 which is located outside of thepatient's body to receive and guide the core wire. The introducer ispreferably not inserted into the annulus fibrosus 122 but can bepositioned either away from the fissures or tear 44 or on the sameposterior aspect (not shown).

FIG. 5B demonstrates the guide wire 510 inserted through the hub 545 andintroducer 540 through the body to the nucleus pulposus 120. The guidewire 510 has sufficient rigidity and torsional characteristics such thatthe guide wire is advanced through the introducer 540 and navigatesalong or through the inner wall of the annulus fibrosus. The distalportion 530 of the guide wire is then positioned along the annularfissure or tear before treatment.

FIG. 5C illustrates the guide wire 510 remaining in place after theintroducer is removed, thus leaving no sharpened structures along thepath of the guide wire. The distal portion 530 remains placed along theposterior inner wall of the annulus near the tear.

Referring to FIG. 5D, a dialator sheath 550 is inserted over the guidewire 510. Sheath 550 performs a similar function as a guiding catheterwhich is known in the art. The sheath supports the catheter (not shown)and guide wire when the catheter is advanced through the bodypercutaneously and also protects the catheter from any collateral damagethat may be associated when the catheter is inserted over the guidewire. Sheath 550 also provides a conduit for the catheter into thenucleus in the event that the catheter would encounter some resistancewhich could damage the treatment modalities associated with thecatheter.

In FIG. 5E, the catheter 500 is inserted into the disc through sheath550. Catheter 500 has a distal portion 531 which is configured to adesired treatment modality and function such as ablation of nucleuspulposus material by the delivery of energy, shrinkage or associatedcollagen structures near the annular fissure or tear 44 by delivery ofenergy, suction of extraneous herniated material, delivery ofmedicaments for the relief of pain associated with a fissure orherniation, insertion of a balloon catheter for expansion of the nuclearmaterial, ultrasound monitoring, visual monitoring of the nucleus orannulus via fiber optic or diagnostic delivery of fluoroscopicsolutions. In a preferred embodiment, the catheter 500 includes aheating element at or near the distal portion 531 such that the annularfissure may be treated with thermal energy such that the fissure issealed. It will be appreciated that the guide wire 510 may remain inplace and catheter 500 may be “exchanged” such that different functionalcatheters as described above may be inserted and withdrawn to perform aspecific function or a variety of separate functions. This isadvantageous in that the traumatic effect of a percutaneous surgicalprocedure is limited in that a single surgical site may provide varioustreatments without the need for multiple surgical sites.

FIG. 5F illustrates the removal of the sheath 550 of FIG. 5E such thatthe guide wire 510 remains within the nucleus pulposus and the flexibledistal portion remains positioned along the posterior inner wall of theannulus. The catheter 500 remains in place over guide wire 510 and thedesired function may be performed along the desired portion of theintervertebral disc.

An alternative embodiment of the apparatus of the present invention isillustrated in FIG. 5G. The sheath 550 remains in place percutaneouslywith catheter 500. The guide wire is removed from the inner lumen of thecatheter 500. Distal tip 531 of the catheter remains in place due to thesemisolid characteristics of the nucleus pulposus 120. The desiredfunction may still be performed along the inner wall such as at theannular fissure 44.

The materials that make up the various parts of an apparatus of theinvention have the following characteristics: the guide wire 510component has a preferable tensile strength of 600-2000 Mpa. The percentelongation of the guide wire is from 5-100 with a desired geometry of0.2-2.3 mm. Preferably, there is little conductivity Tensile strengthand % elongation can be measured according to ASTME8 (tension test ofmetallic materials). Conductivity and resistivity can be determined byprocedures to be found in ASTM Vol. 2.03 for electrothermal properties.The heating element has at least a 300 Mpa tensile strength with a %elongation of 20%. The conductivity of the heating element is preferablyin the range of 0.025-0.2 cal/cm2/cm/sec/C with a resistivity of500-1500.

The diameter of the guide wire is preferably between 0.0020-0.0050inches. The actual dimensions of the guide wire will vary with thestiffness and tensile strength of the material used to form the guidewire. The guide wire may also have various other shapes other thantapered or a flattened ribbon such as triangular, oval, wedge orrectangular in cross-sectional shape. The guide wire preferably has atotal length greater than or at least equal to the length of thecatheter. The guide wire may be manufactured from a high strength alloycontaining cobalt, nickel, chromium or to a composite product having aportion formed of an alloy and a pseudoelastic alloy such as NiTi(NITINOL). Other materials include 304 and 316 stainless steel,semi-hard metals, fully hard metals, Elgiloy from Elgiloy LimitedPartnership, Haynes 188 from Haynes International and MP35N (acobalt-nickel alloy) from Carpenter Technology Corporation.

The catheter has a diameter in the range between 0.0020-0.0068 incheswith a 0.0038 inch preferred diameter. The catheter sheath is preferablypolyimide but may be any biocompatible material such as polyurethane,polyester, rayon, polyamide and silicone. The sheath may be a braidedstructure such that the flexibility of the catheter may be adjusted byvarying the tightness of each braided section. The length of thecatheter is in the range of 3.9 inches to 23.6 inches (10 cm to 60 cm,respectively). The interior of the catheter may also be coated such thatthe outer sheath has support characteristics. Such coatings include butare not limited to silicone, polyimide and the like. The inner liningand coating also provide for a smooth gliding over the guide wire toprevent kinking or snagging of the catheter.

Referring to FIG. 6A, a specific embodiment of the core guide wire 610with a distal hooking tip 635 is illustrated to fix the modular guidewire to the interior annulus wall after final position is achieved.Thus, displacement of the guide wire is prevented during subsequentexchange and withdrawal of other system components. The guide wire 610is inserted through the introducer (not shown) and navigated to adesired portion along the inner wall of the annulus. Distal locking tip635 is inserted and held in place such that the distal portion 630remains in place. The catheter 600 slides through sheath 650 into thenucleus 120 of the intervertebral disc. The distal portion 631 ofcatheter 600 is positioned at the annular fissure 44 for performing afunction as described above. FIG. 6B illustrates the catheter 700 placedwithin the intervertebral disc with sheath 650 removed.

In another specific embodiment, the guide wire has a cross-lockingconfiguration to fix the modular guide wire to the interior annuluswall. FIG. 7A illustrates a guide wire 710 passing through an introducersheath 750 and being navigated along the annulus wall and locked intoplace with distal locking tip 735. Flexible distal portion 730 iscrossed-over the guide wire 710 and locked into an anterior portion ofthe disc. The catheter 700 is slid over the guide wire 710 to placedistal portion 731 within the nucleus pulposus along annular fissure 44.FIG. 7B illustrates the catheter 700 in place without the sheath 750.

FIG. 8A depicts one specific embodiment of a catheter 800 over guidewire 810. Guide wire 810 is placed within intervertebral disc 118 anddistal portion 830 and distal tip 820 are positioned along the posteriorinner wall of the annulus. Sheath 850 is placed into the intervertebraldisc 118 for introduction of catheter 800. Distal portion 831 of thecatheter 800 is shown over the guide wire 810.

In a detail figure, FIG. 8B illustrates the catheter 800 incross-section according to the present invention over a section of theguide wire 810. The distal tip 821 of heating catheter 800 has anopening into the lumen 801 for passing over the guide wire 810. Theinternal lumen near the distal portion 831 contains a heating coil 860for resistive heating. The heating coil 860 is electrically connected toan electrosurgical generator at the proximal portion of the catheter(not shown). A thermal sensor 870 such as a thermocouple is alsopositioned at the distal portion 831 of the catheter 800. A pottingmaterial can be used to fix the position of the thermal sensor 870 andprovide a larger area from which to measure the temperature within thearea. The thermal sensor 870 is connected by conductor 872 to a sensorlocated preferably within the electrosurgical generator but alternatelywithin a separate unit. The sensor is of conventional design, includingbut not limited to a thermistor, T type thermocouple with copperconstantan junction, J type, E type, and K type thermocouples, fiberoptics, resistive wires, infrared detectors, integrated circuits and thelike. Optionally, there may be a separate lumen for the thermal sensorconnection.

FIG. 8C shows a detailed cross-section of the arrangement of the guidewire 810 within catheter 800. Electrical conductor 862 is connected toheating element 860. Thermal sensor 870 is illustrated within thecross-section of the catheter. The arrangement of the conductors,thermal sensors and guide wire within the catheter are meant forillustration only and any suitable arrangement will be appreciated bythose skilled in the art.

FIGS. 9A and 9B illustrate another specific embodiment of a distal tipof a core guide wire according to the invention. Guide wire 910 may beconfigured to have a locking distal tip 935. Hooking element 934 extendsout of distal tip 935 to anchor the tip within the annular wall. FIG. 9Billustrates the hooking element 934 retracted into a lumen within thedistal portion 930 of the guide wire 910. The hooking element 934 may bedeployed by a slight twisting or push-pull on the guide wire 910 suchthat the hook engages the annular wall to hold the guide wire.

FIG. 10 is another specific embodiment of the present invention with asubstantially constant diameter core guide wire 1010 with a flexibledistal portion 1030. The flexible distal portion further has coils 1015for added flexibility at the distal tip. Distal tip 1035 is a lockingtip with hooks 1036 along an edge of the distal tip. The hooks 1036 areoriented such that a clockwise twist of the guide wire 1010 will lockthe tip into the annulus inner wall. A counterclockwise twist willrelease the guide wire from being locked.

In FIG. 11, the shaped memory characteristics of the guide wire areillustrated. The guide wire 1110 is substantially straight along aproximal portion of the core wire. The distal portion 1130 is pre-shapedinto a curve shaped such that the distal tip 1120 will curve toward theguide wire after deployment such as in the cross-locking embodimentdescribe above in FIG. 7A. It will be appreciated that any pre-shapedconfiguration may be used to define the distal portion of the guidewire.

Turning now to FIG. 12, various thermal energy elements are illustrated.The thermal energy element may be positioned around an exterior of thecatheter or within the lumen of the catheter as depicted in FIG. 8B. Forinstance, the thermal energy element may be an integrated structuralelement with the catheter sheath or the element may be separatelyconstructed as a circuit and mounted to the catheter by epoxy or otherattachment method known within the art. The thermal energy element mayalso be biased in that the element may be mounted differentially alongone side of the catheter such that a preferential treating occurssubstantially along only a portion of the catheter. Suitable materialsfor the heating element include but are not limited to stainless steel,NITINOL, nickel/chromium allows, platinum and the like. The heatingelement may also be a polymeric structure with differing flexcharacteristics to provide some support to the catheter near the distaltip.

In one embodiment, the thermal energy element 1260 is a resistiveheating coil. The resistive material is electrically insulated andsubstantially no current escapes into the body. With increasing levelsof current, element 1260 may heat the annulus to greater temperaturelevels without a change in the structure of the coil. A specificembodiment of a temperature level is approximately 55 C at a specifictarget site such as an annular fissure. The range for heat is from 45 Cto 75 C.

In another embodiment, sufficient energy is delivered to theintervertebral disc to heat and shrink the collage component of theannulus fibrosus and/or nucleus pulposus but not to ablate anysurrounding tissue adjacent to the catheter. The heating coil isconfigured to seal the fissure without damage to surrounding tissue. Itis believed that the injury to the intervertebral disc tissue and thebody's own healing response leads to a marked improvement

FIG. 12B illustrates a heating element 1261 which is a flat element. Theflat elements may be etched onto a surface of the catheter or separateelement to be bonded to the catheter by chemical etching,electrochemical etching, photo etching or physical etching.Additionally, the flat heating elements 1261 may be chemically,electrically or physically deposited onto the surface. Similarly, inFIG. 12C, the heating element may be in the form of a flex ribbonheating element 1262. Each heating element 1261 may be individuallyconnected to the electrosurgical generator to deliver power and energyeither in parallel or series such that the energy is delivered betweeneach element and through the tissue.

In another specific embodiment, FIG. 12D illustrates a heating elementcomprised of a section of the core guide wire 1210 in the form of amonofilament 1263. A proximal portion 1265 of the guide wire hasinsulation to prevent heating of the guide wire at that portion. Distalportion 1220 is used as the heating element to deliver thermal energy tothe desired site.

Additionally, a radiographically opaque marking device can be includedin the distal portion of the catheter (such as in the tip or at spacedlocations throughout the intradiscal portion) so that advancement andpositioning of the intradiscal section can be directly observed byradiographic imaging. Such radiographically opaque markings arepreferred when the intradiscal section is not clearly visible byradiographic imaging, such as when the majority of the catheter is madeof plastic instead of metal. A radiographically opaque marking can beany of the known (or newly discovered) materials or devices withsignificant opacity. Examples include but are not limited to a steelmandrel sufficiently thick to be visible on fluoroscopy, atantalum/polyurethane tip, a gold-plated tip, bands of platinum,stainless steel or gold, soldered spots of gold and polymeric materialswith radiographically opaque filler such as barium sulfate. A resistiveheating element or a RF electrode(s) may provide sufficientradio-opacity in some embodiments to serve as a marking device.

In a specific embodiment, temperatures delivered through the heatingelement may be detected at sensors to provide feedback for maintaining aselected power in the electrosurgical generator. The actual temperaturesare measured at a temperature measurement device, and the temperaturesare displayed at a user interface and display. A control signal isgenerated by a controller that is related to the actually measuredtemperature and a desired temperature. The control signal is used bypower circuits to adjust the power output in an appropriate amount inorder to maintain the desired temperature delivered at the respectivesensor. A multiplexer can be included to measure current, voltage, andtemperature at the sensors so that appropriate energy can be deliveredto resistive heating elements.

It will also be appreciated by one skilled in the art that the core ofthe guide wire can also provide the function of differential flexibilityby varying the thickness in one or more dimensions (for example, the“thin” dimension, the “thick” dimension, or both) along the length ofthe guide wire. A guide wire that tapers (becomes gradually thinner)toward the distal tip of the guide wire will be more flexible and easierto bend at the tip than it is at other locations along the guide wire. Aguide wire that has a thicker or more rounded tip than more proximalportions of the mandrel will resist bending at the tip but aid bendingat more proximal locations. Thickening (or thinning) can also occur inother locations along the guide wire. Control of the direction ofbending can be accomplished by making the guide wire more round, i.e.,closer to having 1:1 diameter ratios; flatter in different sections ofthe guide wire; or by varying the absolute dimensions (increasing ordecreasing the diameter). Such control over flexibility allowsinstruments within a catheter over the guide wire to be designed thatminimize bending in some desired locations (such as the location ofconnector of an electrical element to avoid disruption of theconnection) while encouraging bending in other locations (e.g., betweensensitive functional elements). In this manner, a guide wire that isuniformly flexible along its entire length, is variably flexible alongits entire length, or has alternating more flexible and less flexiblesegment(s), is readily obtained simply by manufacturing the guide wirewith appropriate thickness at different distances and in differentorientations along the length of the guide wire. Such a catheter willhave two or more different radii of curvature in different segments ofthe guide wire and catheter under the same bending force.

Some characteristics of alternative guide wires include steerabilitywith a 1:1 torque response; formability with a ribbon to allow thephysician to shape a “J” curve on the tip. The guide wire also hasflexible characteristics in order to negotiate tortuous anatomy andtight lesions without damaging the guide wire or associated catheter.The guide wire may also be tracked so that a balloon catheter is able tomove over the wire with minimum resistance. The guide wire is alsopreferably radiopaque so as to be visible under fluoroscopy.

The foregoing description of specific embodiments of the invention havebeen presented for purposes of illustration and description. They arenot intended to be exhaustive or to limit the invention to the preciseforms disclosed. Obviously, many modifications and variations will beapparent to practitioners skilled in this art. The embodiments werechosen and described in order to best explain the principles of theinventions and its practical application, to thereby enable othersskilled in the art to best utilize the invention and various embodimentswith various modifications as are suited to the particular usecontemplated. It is intended that the scope of the invention be definedby the following claims and their equivalents.

1. An apparatus for accessing a selected section of an intervertebraldisc comprising: a catheter having a lumen; and a guide wire having adistal portion and a proximal portion, and configured to be positionedwithin and moved relative to the lumen of the catheter, wherein theguide wire is capable of navigating itself within an intradiscal sectionof an intervertebral disc to a selected section of the disc and thecatheter is capable of being advanced relative to the guide wire suchthat the catheter follows a path of the guide wire within theintradiscal section of the disc adjacent an inner wall of an annulus ofthe disc to the selected section, wherein the guide wire has (a)sufficient rigidity to be advanceable through a nucleus pulposus and theannulus fibrosus under a force applied longitudinally to the proximalportion of the guide wire, and (b) insufficient penetration ability tobe advanceable out through the annulus fibrosus under the applied force.2. The apparatus according to claim 1, wherein the guide wire hassufficient flexibility in a direction of a disc place to be compliantwith an inner wall of the annulus of the disc.
 3. The apparatusaccording to claim 1, wherein the distal portion of the guide wireincludes a spring coil.
 4. The apparatus according to claim 3, whereinthe spring coil contains a forming ribbon.
 5. The apparatus according toclaim 1, wherein the distal portion of the guide wire is tapered to asmaller diameter toward the distal end.
 6. The apparatus according toclaim 1, wherein the distal portion of the guide wire has a distal tipat the extremity of the distal portion of the guide wire.
 7. Theapparatus of claim 6, wherein the distal tip is configured to benon-piercing through an annulus fibrosus.
 8. The apparatus according toclaim 6, wherein the distal tip is a blunt tip.
 9. The apparatusaccording to claim 6, wherein distal tip is a rolling ball tip.
 10. Theapparatus according to claim 1, wherein the distal portion of the guidewire includes a locking mechanism for securing the guide wire within theselected section of the disc, the locking mechanism including a piercingtip.
 11. The apparatus according to claim 10, wherein the lockingmechanism includes a retractable hook.
 12. The apparatus according toclaim 10, wherein the locking mechanism includes a plurality ofdirectional hooks.
 13. The apparatus according to claim 12, wherein theplurality of directional hooks are configured to secure the guide wirewithin the selected section of the disc by rotating the hooks in a firstdirection, and to release the guide wire from the selected section ofthe disc by rotating the hooks in a second direction that issubstantially opposite to the first direction.
 14. The apparatusaccording to claim 10, wherein the guide wire is capable ofcross-locking itself once the guide wire is advanced to the selectedsection of the disc.
 15. The apparatus according to claim 12, whereinthe locking mechanism comprises a hook.
 16. The apparatus according toclaim 12, wherein the distal portion of the guide wire forms the lockingmechanism.
 17. The apparatus of claim 12, wherein the distal portion ofthe guide wire has a distal tip that includes the piercing tip.
 18. Theapparatus according to claim 12, wherein the piercing tip is configuredto secure the guide wire by piercing the selected section of the disc.19. The apparatus according to claim 12, wherien the piercing tip isconfigured to secure the guide wire against movement in all directions.20. The apparatus according to claim 1, wherein the proximal portion ofthe guide wire has an outer diameter between about 0.005-0.025 inches.21. The apparatus according to claim 1, wherein the distal portion ofthe guide wire has an outer diameter between about 0.002-0.012 inches.22. The apparatus according to claim 1, wherein the proximal portion ofthe guide wire is between about 10-15 inch long.
 23. The apparatusaccording to claim 1, wherein the distal portion of the guide wire isbetween about 0.2-1.2 inch long.
 24. The apparatus of claim 1, whereinthe distal portion of the guide wire has a length at least one-half of adiameter of the nucleus pulposus.
 25. The apparatus of claim 1, whereinthe apparatus further comprises a dialator sheath configured to be slidover the guide wire for introducing the catheter onto the guide wire.26. The apparatus of claim 1, wherein at least a portion of the guidewire is actively steerable.
 27. The apparatus of claim 1, wherein atleast a portion of guide wire is radiographically visible.
 28. Theapparatus of claim 1, wherein the distal portion of the guide wire hasone or more flat sides.
 29. The apparatus of claim 1, wherein the guidewire has a bending stiffness as measured in Taber stiffness unitsbetween about 2-400 units in a desired bending plane.
 30. The apparatusof claim 1, wherein the guide wire has a bending stiffness as measuredin Taber stiffness units between about 3-150 units in a desired bendingplane.
 31. The apparatus of claim 1, wherein the distal portion of theguide wire has a column strength between about 0.2-7 kg.
 32. Theapparatus of claim 1, wherein the distal portion of the guide wire has acolumn strength between about 0.7-4 kg.
 33. The apparatus of claim 1,wherein the catheter further includes a functional element forperforming a function adjacent the selected section.
 34. The apparatusof claim 33, wherein the function is selected from the group consistingof delivering energy, adding material and removing material.
 35. Theapparatus of claim 33, wherein the functional element comprise a thermalenergy delivery device.
 36. The apparatus of claim 35, wherein a thermalenergy source is operably attached to the thermal energy delivery devicethrough the catheter.
 37. The apparatus of claim 35, wherein the thermalenergy delivery device is selected from the group consisting ofmicrowave probe, optical fiber, radio frequency electrode and ultrasoundemitter.
 38. The apparatus of claim 35, wherein the thermal energydelivery device is a resistive heater.
 39. The apparatus of claim 35,wherein the catheter further comprises at least one sensor capable ofmonitoring temperature, power, voltage or a combination thereof and theinput from the sensor controls energy supplied to the thermal energydevice.
 40. The apparatus of claim 33, wherein the functional elementcomprises an irrigation lumen extending from a proximal end of thecatheter to the intradiscal section.
 41. The apparatus of claim 33,wherein the functional element is capable of delivering a controlledamount of energy at or near the fissure such that no vaporization occursat or near the fissure when energy is delivered by the functionalelement.
 42. The apparatus of claim 33, wherein the functional elementis capable of delivering a controlled amount of energy at or near thefissure such that no material other than water is removed at or near thefissure when energy is delivered by the functional element.
 43. Theapparatus of claim 33, wherein the functional element is capable ofdelivering a controlled amount of energy at or near the fissure suchthat no destructive lesion is formed on a disc at or near the fissurewhen energy is delivered by the functional element.
 44. An apparatus foraccessing a selected section of an intervertebral disc comprising: acatheter having a lumen; and a guide wire having a distal portion and aproximal portion, and configured to be positioned within and movedrelative to the lumen of the catheter, wherein the guide wire is capableof navigating itself within an intradiscal section of an intervertebraldisc to a selected section of the disc and the catheter is capable ofbeing advanced relative to the guide wire such that the catheter followsa path of the guide wire within the intradiscal section of the discadjacent an inner wall of an annulus of the disc to the selectedsection, wherein the guide wire has sufficient flexibility in adirection of a disc plane to be compliant with the inner wall of theannulus of the disc.
 45. An apparatus for accessing a selected sectionof an intervertebral disc comprising: a catheter having a lumen; and aguide wire having a distal portion and a proximal portion, andconfigured to be positioned within and moved relative to the lumen ofthe catheter, wherein the guide wire is capable of navigating itselfwithin an intradiscal section of an intervertebral disc to a selectedsection of the disc and the catheter is capable of being advancedrelative to the guide wire such that the catheter follows a path of theguide wire within the intradiscal section of the disc adjacent an innerwall of an annulus of the disc to the selected section, wherein thedistal portion of the guide wire has a rolling ball tip at the extremityof the distal portion of the guide wire.
 46. An apparatus for accessinga selected section of an intervertebral disc comprising: a catheterhaving a lumen; and a guide wire having a distal portion and a proximalportion, and configured to be positioned within and moved relative tothe lumen of the catheter, wherein the guide wire is capable ofnavigating itself within an intradiscal section of an intervertebraldisc to a selected section of the disc and the catheter is capable ofbeing advanced relative to the guide wire such that the catheter followsa path of the guide wire within the intradiscal section of the discadjacent an inner wall of an annulus of the disc to the selectedsection, wherein the guide wire has a middle portion disposed betweenthe proximal and distal portions, and the middle portion is moreflexible than both the proximal portion and the distal portion.
 47. Anapparatus for accessing a selected section of an intervertebral disccomprising: a catheter having a lumen; and a guide wire having a distalportion and a proximal portion, and configured to be positioned withinand moved relative to the lumen of the catheter, wherein the guide wireis capable of navigating itself within an intradiscal section of anintervertebral disc to a selected section of the disc and the catheteris capable of being advanced relative to the guide wire such that thecatheter follows a path of the guide wire within the intradiscal sectionof the disc adjacent an inner wall of an annulus of the disc to theselected section, wherein the guide wire has a middle portion disposedbetween the proximal and distal portions, and the middle portion is lessflexible than both the proximal portion and the distal portion.
 48. Anapparatus for accessing a selected section of an intervertebral disccomprising: a guide wire having a distal portion and a proximal portion,the guide wire being capable of navigating itself within an intradiscalsection of an intervertebral disc to a selected section of the discalong a path at least partially adjacent an inner wall of an annulus ofthe disc, wherein the guide wire has (a) sufficient rigidity to beadvanceable through a nucleus pulposus and the annulus fibrosus under aforce applied longitudinally to the proximal portion of the guide wire,and (b) insufficient penetration ability to be advanceable out throughthe annulus fibrosus under the applied force.